Physical and Chemical Behavior of Solids. 219 



Table II. Lowering of Melting Point of Metals effected by one 



atm. unequal pressure ; together with the computed 



melting pressures at ordinary temperatures. 



Metal 



Melting point 



Heat of 

 fusion 



Density 



ATx* 



027f 





t 



r, 



" 









K 



62 



335 



15-7 



0-87 



0-59 



64 



Na 



97 



370 



31*7 



98 



•29 



266 



Pb 



327 



600 



5*4 



11-37 



•24 * 



1760 



Sn 



232 



505 



14-1 



7-29 



•12 



2200 



Bi 



270 



543 



12-5 



9-80 



•11 



3000 



Cd 



321 



594 



13*7 



8-64 



•12 



3300 



Al 



653 



931 



42' 



2-60 



•21 



5100 



Zn 



419 



692 



28' 



7-1 



•084 



6900 



Ag 



900 



1233 



23' 



10-50 



•12 



14000 



Cu 



1083 



1356 



43' 



8-93 



•086 



24000 



Pd 



1550 



1823 



36'3 



11-4 



•11 



31000 



Pt 



1755 



2028 



27'2 



21-5 



•084 



46000 



*This column, which represents the melting point depression produced by 

 one atm. excess pressure acting on the solid, is given merely to exhibit the 

 magnitude of this quantity The values given are calculated from the 

 formula 



A2 1 ! = 



r, 



41 30 Q D 



which is easily derived from equation III. 



fit should be observed that the values of </> given in the preliminary note 

 (J. Washington Acad. Sci., i, 260, 1911) were calculated by a formula which 

 holds strictly only so long as either <j> or the difference between T x and T 2 is 

 small. The more accurate mode of calculation from equation V of the 

 present paper leads to somewhat higher numerical values of 0. but does not 

 alter the order of the <j> values ; so that this change does not affect the argu- 

 ment. 



(a) tensile strength, elastic limit, hardness ; (b) compressibility, 

 elastic modulus, rigidity modulus; as is shown by Table III. 

 The exceptions to this statement are very few as regards any 

 one property, and vary irregularly as we pass from one property 

 to another ; in other words, there are no systematic devia- 

 tions between the sequence of the $ values and that obtained 

 when the metals are arranged progressively with reference to 

 any one of their mechanical properties for which measurements 

 have been made. The slight divergences are no greater than 

 one might expect from the uncertain character of the thermal 

 data, on the one hand, and of the elastic constants on the other. 

 This remarkable concordance establishes the fact that the 

 mechanical properties of metals are in some way correlated 



